This invention relates generally to fastening systems for joining one joint member or panel or another joint member or panel such as in furniture, shelving, storage bins, racks, phone booths, room space dividing panels, decorative panels, frames, storage assemblies or the like, and more particularly, to a fastener clip assembly for forming a joint between joint members or panels for such structures.
Many joints, such as between modern furniture parts, are fastened together by concealed mechanical connectors. Many of these concealed fasteners employ keyhole type slots and stud-like fasteners. Generally, this type of fastening system includes short recessed areas along the edges of the joint members such as furniture panels to be joined together. One or more fasteners are mounted within the recessed area of one joint member or furniture piece and a stud is mounted on the other. The fastener engages the head of the stud in a keyhole slot, then seats the stud to firmly engage the separate joint members or furniture panels. See, for example, U.S. Pat. Nos. 6,109,819; 4,473,316; 4,470,716; 4,332,205; and 4,178,047.
While functioning well to securely join the two joint members or furniture panels together in a secure joint, many prior systems have been prone to encounter rotation during assembly of the panels since the securing stud is typically mounted on an exposed surface even though the fastener clip receiving that stud is secured in a recessed pocket. Typically, there is no structure on the securing stud for engagement with the receiving clip to prevent rotation between the joint panels. A proposed solution to this drawback has been to secure the stud in the recessed pocket and place the receiving clip on an exposed surface of the opposite panel. In such case, the walls of the recessed pocket serve to confine and prevent significant rotation of the fastener clip when joined with the securing stud. However, unless precisely aligned, the clip can engage the walls of the pocket and, when significant force is applied such as is needed to fully assembly the fastener clip and securing stud, misalignment can break the walls of the pocket and damage the panel joint. Alternately, application of excessive force can also break the pocket walls.
Yet another solution to the rotation problem has been to provide an extra long recessed pocket in which a pair of fastener clips are mounted end to end for engagement with a pair of spaced securing studs. Hence, when the pair of studs is received in the aligned clips, rotation between the joint panels is prevented. However, this solution in effect doubles the cost of the required joint by adding a second securing system even though a single system would have sufficient strength to hold the panel members together to adequately hold the panel members. In addition, this solution requires a large amount of additional space for mounting the fasteners thereby preventing use in confined areas or where extra length is not available.
Yet another problem has been a lack of strength in prior fastener systems due to the inclusion of a single securing stud or fastener screw engaging an opposing fastener clip. When strong forces are applied to the joint members, the threads of the single securing screw bear the entire force of retaining the joint together. Hence, premature failure of such joints has been encountered when the joints are subject to strong forces.
Accordingly, the need exists in the furniture and other industries for a fastener system which prevents rotation between the joined parts or panels and minimizes damage to those joint members or panels while providing the benefits of increased strength, substantial concealment of the joint to provide a finished appearance, or to prevent vandalism, as well as ease of assembly, ease of use in automatic feed/manufacturing systems, and ease of disassembly in applications requiring same.
Therefore, the present invention provides an improved fastener system and joint structure incorporating same which provides a strong, secure joint which can be easily assembled while alternately providing ease in disassembly where desired, while preventing rotation between the joined clip and joint members in a manner which avoids damage to the joint members.
In one embodiment, the invention is a clip assembly for forming a joint structure to secure a first joint member to a second joint member, the clip assembly comprising a first clip having at least one and preferably a pair of spaced first mounting portions for attachment to the first joint member and a second clip adapted for attachment to the second joint member and for assembly with the first clip. The first clip includes a first engagement section offset from and connected to the first mounting portion or portions and a slot extending along the engagement section. The slot has a first portion with a predetermined width. The second clip has at least one, and preferably a pair of spaced second mounting portions, a second engagement section offset from and connected to the second mounting portion or portions, and at least one portion of the second engagement section having a width greater than the first portion of the slot. At least one of the first and second engagement sections has a resilient, flexible, inclined area. When the first clip is assembled to the first joint member, and the second clip is assembled to the second joint member, and the second clip is assembled to the first clip through the slot of the first engagement section, the first and second engagement sections engage one another with one portion of the second engagement section overlying the slot of the first engagement section while the resilient, flexible inclined area urges the clips and first and second joint members toward one another to form a tight, secure joint.
Preferably, each of the first and second engagement sections is a resilient, flexible inclined area such that the inclined areas engage one another upon assembly of the clips. These inclined areas may be arcuate, curved portions having intermediate apexes which engage one another upon assembly.
Either the engagement sections themselves or the overall clips may be formed from spring steel or another flexible, resilient material which returns to its original configuration when disassembled. The mounting portions may preferably comprise coplanar mounting flanges connected to opposite ends of each engagement section by upstanding legs. One of the legs on the second clip may be narrower than the other leg and have a width less than that of the slot such that the narrower leg may be received through the slot when the clips are telescoped together for assembly.
In other aspects, portions of the slot may be narrowed, or portions of the connecting legs between the mounting flanges and the engagement sections may be widened, to provide a wedging action upon assembly to further prevent rotation between the clips and the resulting joint.
In yet further aspects of the invention, the clips may be formed in semi locking or locking versions. In the semi locking version, the slot includes a tapered slot section through which a portion of the second clip is received during assembly, the tapered slot section resisting disassembly when the clips are fully assembled.
In the locking version, a locking member is provided on the first clip for engaging a receiving portion on the second clip to resist disassembly when the clips are fully assembled. In various forms, the locking member may be a locking flange extending from a position spaced from the first engagement section toward the first engagement section, while a portion of the second clip may include a receiving area engaged by a free end of the locking flange. Variations of the receiving area may include a raised protrusion extending outwardly from the second engagement area, a plurality of spaced protrusions on the second engagement area, or an aperture in the second engagement area of the first clip.
In another form of the invention, the clip assembly of the present invention includes a first clip and a second clip as described above, along with an engaging member on at least one of the first and second clips. The engaging member engages a portion of the other of the first and second clips when the clips are assembled to resist disassembly of the clips. Thus, when the clips are assembled, the first and second engagement sections engage one another with the second engagement section overlying the slot of the first engagement section while the engaging member resists disassembly of the clips.
In yet further forms of the invention, a joint assembly is provided including first and second joint members and a clip assembly in accord with any one of the variations described above.
Accordingly, the present invention provides a fastener system including a clip assembly which resists and prevents rotation between the clip members when assembled as well as the corresponding joint members secured by the clip members, has improved strength over prior known fastening systems, yet provides a substantially hidden/concealed joint for improved aesthetic appearance of the joint or prevention of vandalism. The clip assembly provides ease of assembly while allowing larger tolerances in the joint members for proper operation without requiring expensive, precise machining prior to installation. A variety of clip forms are available for non locking, semi locking and fully locking installations. The clip assembly is compatible with existing boring machines and methods and can be easily manufactured from a single blank of material regardless of the variation desired.
These and other objects, advantages, purposes and features of the invention will become more apparent from a study of the following description taken in conjunction with the drawings.